(see, e.g., [1]}).
By (REF ) and (REF ), we have
\(&\sup _{t \in [0, 1]^m} \bigg |\sum _{k_1, \cdots , k_m \in \mathbb {N}} w_{k_1, \cdots , k_m} \cdot \mathcal {T}_m(\psi _{k_1} \otimes \cdots \otimes \psi _{k_m})(t) \bigg | \\&\qquad = \sup _{s \in [0, 1]^m} \bigg |\sum _{k_1, \cdots , k_m \in \mathbb {N}} w_{k_1, \cdots , k_m} \\&\qquad \qquad \qquad \qquad \qquad \cdot \int _{s_1}^1 \cdots \int _{s_m}^1 (z_1 - s_1) \cdots (z_m - s_m) \phi _{k_1}(z_1) \cdots \phi _{k_m}(z_m) \, dz_m \cdots \, dz_1 \bigg | \\&\qquad = \left\Vert w\right\Vert _{Z^{\circ }}\) 
